1. Field of the Invention
The present invention generally relates to Ethernet extension. More particularly, the present invention relates to a bridge-based Radio Access Station (RAS) backbone network system in which a RAS backbone network that forms the backbone of a wireless system is built by Ethernet technology and a signal processing method therefore.
2. Description of the Related Art
Ethernet is one of the most widely used technologies for Local Area Network (LAN). Due to its universality and simple structure, the use of Ethernet is being extended to very LAN and Wide Area Network (WAN).
FIG. 1 illustrates an exemplary configuration of a conventional Wireless Broadband (WiBro) RAS backbone network. Referring to FIG. 1, the WiBro RAS backbone network includes a plurality of RASs 10 and Access Control Routers (ACRs) 12 for controlling the RASs 10. The WiBro network may further include a Home Agent (HA, not shown) for supporting the mobility of Mobile Nodes (MNs) and an Authentication, Authorization, Accounting (AAA) server 14 for performing authentication, authorization, and accounting for users and MNs in order to allow network access and provide services to authorized users only.
The RASs 10 have their service areas, i.e. cells and provide services to a plurality of Customer Equipments (CEs) 11 within the cells, such as portable phones, Personal Digital Assistants (PDAs), and laptops. The RASs 10 transmit/receive signals to/from the CEs 11 on radio channels. The RASs 10 are also connected to the ACRs 10 by cable, each ACR being a router forming an Internet Protocol (IP) subnet. A radio signal from a CE 11 is encapsulated in an IP packet by a RAS 10 and then transmitted to an upper ACR 12′. The ACR 12′ switches the IP packets to a neighbor ACR 12″ close to a recipient according to the IP address of the recipient. In this manner, communications are conducted in IP packets and the recipient is located by his IP address in the conventional RAS backbone network.
As illustrated in FIG. 1, however, the conventional RAS backbone network is configured mainly with Layer 3 (L3) routers. The resulting relative high complexity in network configuration renders network management inefficient. Also, since handover occurs in L3, the handover takes much time.